Data Transmission Method and Apparatus

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No. PCT/CN2021/114164, filed on Aug. 24, 2021, which claims priority to Chinese Patent Application No. 202011126518.1, filed on Oct. 20, 2020. The disclosures of the aforementioned applications are hereby incorporated by reference in their entireties.

TECHNICAL FIELD

This application relates to the field of communication technologies, and specifically, to a data transmission method and apparatus.

BACKGROUND

A Wireless Fidelity (Wireless-Fidelity, Wi-Fi) network is a widely used wireless local area network (wireless local area network, WLAN), and is usually used in indoor places such as residential environments. The development and popularization of smart home, distance education, home office, live video streaming, and virtual reality (virtual reality, VR) pose high requirements on the bandwidth, latency, and coverage of Wi-Fi networks in residential environments. Therefore, based on fiber to the home (fiber to the home, FTTH), the industry proposes a fiber to the room (fiber to the room, FTTR) network solution. In an FTTR architecture, a Wi-Fi access point is connected to a network-side device (for example, a gateway (gateway)) of the Wi-Fi access point by using an optical fiber. In this way, data backhaul may be performed over an optical link with high bandwidth and low latency, and no Wi-Fi air interface resource is occupied. This greatly improves a multi-access point coordination effect and data transmission efficiency. Although the problems such as insufficient Wi-Fi coverage and limited backhaul bandwidth are resolved by using the FTTR architecture, seamless Wi-Fi roaming and high throughput still cannot coexist.

SUMMARY

Embodiments of this application provide a data transmission method and apparatus, to provide a better network access manner and a better data transmission mode for a terminal device. According to a first aspect, an embodiment of this application provides a data transmission method, applied to a controller. The controller is configured to control a plurality of access points. The method includes: receiving, by the controller, a performance parameter sent by each of the access points, where the performance parameter indicates communication performance between the access point that sends the performance parameter and a first station; determining, by the controller based on each received performance parameter, an access point set configured to provide a data transmission service for the first station, where the access point set includes at least one of the plurality of access points; and when the access point set includes at least two access points, determining, by the controller, a data transmission mode between each of the access points in the access point set and the first station based on the performance parameter sent by each of the access points in the access point set. That is, a data transmission mode and an access point that provides a data transmission service for a station may be selected based on communication performance between the station and the access point, so that a better network access manner and a better data transmission mode can be provided for the station, thereby improving communication experience of users. In a possible implementation, the performance parameter includes at least one of a received signal strength indication RSSI of a signal sent by the first station and received by the access point, and load information of the access point. That is, in this implementation, an access point that provides a data transmission service for a station may be determined based on a load of the access point and a signal strength between the access point and the station, so that an access point with a light load and a high signal strength can be selected to provide the data transmission service for the station. In a possible implementation, the performance parameter sent by any access point in the determined access point set satisfies that the RSSI is greater than a preset strength threshold, and the load information is less than a preset load threshold. That is, in this implementation, an access point with a load and a signal strength that satisfy a preset requirement is determined to provide the data transmission service for the station. Therefore, network quality of service of the station can be ensured or improved, and communication experience of users can be improved. In a possible implementation, the controller is independent of each of the plurality of access points, or the controller is integrated into one of the plurality of access points. That is, in this implementation, the controller may be flexibly configured to facilitate networking. In a possible implementation, when the controller is independent of each of the plurality of access points, receiving, by the controller over an optical link or a Wi-Fi channel, the performance parameter sent by each of the access points; or when the controller is integrated into one of the plurality of access points, receiving, by the controller over an optical link or a Wi-Fi channel, the performance parameter sent by each of the access points except the access point in which the controller is located. That is, in this implementation, a backhaul (backhaul) channel of the access point may be flexibly selected or configured to facilitate networking. In a possible implementation, the plurality of access points include a first access point and a second access point, and the first station accesses a network through the first access point; and the method further includes: receiving, by the controller, network accessing information of the first station from the first access point; and sending, by the controller, the network accessing information to the second access point. That is, in this implementation, the access points may share the network accessing information of the station. Therefore, each access point may establish a connection to the station based on the network accessing information of the station. In a possible implementation, the network accessing information includes association request information and a key. That is, in this implementation, the network accessing information shared among the access points includes the association request information and the key, and each access point may establish a connection to the station based on the association request information and the key. In a possible implementation, the plurality of access points include a same basic service set identifier BSSID. That is, in this implementation, different access points have a same BSSID, so that the station may be simultaneously connected to a plurality of access points. In a possible implementation, the determining, by the controller, a data transmission mode between each of the access points in the access point set and the first station based on the performance parameter sent by each of the access points in the access point set includes: when the performance parameter corresponding to each of the access points in the access point set does not satisfy a preset performance requirement, determining that different access points in the access point set separately send same data to the first station at different moments. That is, in this implementation, when a channel environment in which the station is located is poor, the plurality of access points may send the same data to the station, thereby increasing a probability that the station successfully receives the data. In a possible implementation, the determining, by the controller, a data transmission mode between each of the access points in the access point set and the first station based on the performance parameter sent by each of the access points in the access point set includes: when the performance parameter corresponding to each of the access points in the access point set satisfies a preset performance requirement, determining that different access points in the access point set separately send different data to the first station at a same moment. That is, in this implementation, when a channel environment in which the station is located is good, the plurality of access points connected to the station may simultaneously send different data to the station, thereby increasing a data throughput of a network. In a possible implementation, the determining, by the controller, a data transmission mode between each of the access points in the access point set and the first station based on the performance parameter sent by each of the access points in the access point set includes: when a performance parameter of a third access point in the access point set satisfies a preset performance requirement, and access points in the access point set except the third access point do not satisfy the performance requirement, configuring the third access point as a primary access point in the access point set, where the primary access point is configured to independently send data to the first station. That is, in this implementation, when a channel environment in which the station is located is average, an access point having good communication performance with the station may be selected to provide a data transmission service for the station, so that both communication quality of service of the station and overall network overheads can be ensured. In a possible implementation, when receiving first data sent by the first station, the primary access point is further configured to send an acknowledge character corresponding to the first data to the first station. That is, in this implementation, one access point is configured to return an acknowledge character to the station, so that a conflict caused when a plurality of access points return acknowledge characters can be avoided. In a possible implementation, the access point set includes a fourth access point and a fifth access point; and the determining, by the controller, a data transmission mode between each of the access points in the access point set and the first station based on the performance parameter sent by each of the access points in the access point set includes: configuring a sending moment at which the fourth access point sends uplink resource configuration information to the first station as a first moment; and configuring a sending moment at which the fifth access point sends the uplink resource configuration information to the first station as a second moment, where the second moment is later than the first moment; and when the first station sends uplink data at the second moment in response to the uplink resource configuration information sent by the fourth access point, the fifth access point no longer sends the uplink resource configuration information to the first station. That is, in this implementation, a sending mechanism of the uplink resource configuration information of the access point is configured, so that a conflict caused when a plurality of access points return acknowledge characters can be avoided. According to a second aspect, an embodiment of this application provides a data transmission method, applied to a first access point in a plurality of access points controlled by a controller. The method includes: determining, by the first access point, a first performance parameter, where the first performance parameter indicates communication performance between the first access point and a first station; and providing a data transmission service for the first station when the first performance parameter satisfies a preset performance requirement. That is, the data transmission service is provided for the station only when the communication performance between the access point and the station satisfies the requirement. Therefore, both network quality of service of the station and overall network overheads can be ensured. In a possible implementation, the method further includes: sending, by the first access point, network accessing information to the controller, where the network accessing information is information obtained by the first access point when the first station accesses a network through the first access point. The controller may send the network accessing information to a second access point in the plurality of access points, so as to share the network accessing information among the plurality of access points. That is, in this implementation, the station may access a network through a single access point, and the access point may send the network accessing information to the controller, for the controller to send the network accessing information to another access point, so that the another access point may be connected to the station without performing an access process. In a possible implementation, the plurality of access points further include a second access point; the first station accesses a network through the second access point; and the method further includes: receiving, by the first access point, network accessing information of the first station from the controller, where the network accessing information is received by the controller from the second access point. That is, in this implementation, the controller may share, with another access point, network accessing information obtained by an access point when the station accesses a network, so that the another access point may be connected to the station without performing an access process. In a possible implementation, the network accessing information includes association request information and a key. That is, in this implementation, the network accessing information shared among the access points includes the association request information and the key, and each access point may establish a connection to the station based on the association request information and the key. According to a third aspect, an embodiment of this application provides a data transmission apparatus, configured to control a plurality of access points. The apparatus includes: a communication unit, configured to receive a performance parameter sent by each of the access points, where the performance parameter indicates communication performance between the access point that sends the performance parameter and a first station; a first determining unit, configured to determine, based on each received performance parameter, an access point set configured to provide a data transmission service for the first station, where the access point set includes at least one of the plurality of access points; and a second determining unit, configured to determine, when the access point set includes at least two access points, a data transmission mode between each of the access points in the access point set and the first station based on the performance parameter sent by each of the access points in the access point set. In a possible implementation, the performance parameter includes at least one of a received signal strength indication RSSI of a signal sent by the first station and received by the access point, and load information of the access point. In a possible implementation, the performance parameter sent by any access point in the determined access point set satisfies that the RSSI is greater than a preset strength threshold, and the load information is less than a preset load threshold. In a possible implementation, the apparatus is independent of each of the plurality of access points, or the apparatus is integrated into one of the plurality of access points. In a possible implementation, when the apparatus is independent of each of the plurality of access points, the communication unit receives, over an optical link or a Wi-Fi channel, the performance parameter sent by each of the access points; or when the apparatus is integrated into one of the plurality of access points, the communication unit receives, over an optical link or a Wi-Fi channel, the performance parameter sent by each of the access points except the access point in which the apparatus is located. In a possible implementation, the plurality of access points include a first access point and a second access point, and the first station accesses a network through the first access point; and the communication unit is further configured to: receive network accessing information of the first station from the first access point; and send the network accessing information to the second access point. In a possible implementation, the network accessing information includes association request information and a key. In a possible implementation, the plurality of access points include a same basic service set identifier BS SID. In a possible implementation, the second determining unit is further configured to: determine, when the performance parameter corresponding to each of the access points in the access point set does not satisfy a preset performance requirement, that different access points in the access point set separately send same data to the first station at different moments. In a possible implementation, the second determining unit is further configured to: determine, when the performance parameter corresponding to each of the access points in the access point set satisfies a preset performance requirement, that different access points in the access point set separately send different data to the first station at a same moment. In a possible implementation, the second determining unit is further configured to: when a performance parameter of a third access point in the access point set satisfies a preset performance requirement, and access points in the access point set except the third access point do not satisfy the performance requirement, configure the third access point as a primary access point in the access point set, where the primary access point is configured to independently send data to the first station. In a possible implementation, when receiving first data sent by the first station, the primary access point is further configured to send an acknowledge character corresponding to the first data to the first station. In a possible implementation, the access point set includes a fourth access point and a fifth access point; and the second determining unit is further configured to: configure a sending moment at which the fourth access point sends uplink resource configuration information to the first station as a first moment; and configure a sending moment at which the fifth access point sends the uplink resource configuration information to the first station as a second moment, where the second moment is later than the first moment; and when the first station sends uplink data at the second moment in response to the uplink resource configuration information sent by the fourth access point, the fifth access point no longer sends the uplink resource configuration information to the first station. It may be understood that, the data transmission apparatus provided in the third aspect is configured to perform the corresponding method provided in the first aspect. Therefore, for beneficial effects that can be achieved by the data transmission apparatus, refer to the beneficial effects of the corresponding method provided in the first aspect. Details are not described herein again. According to a fourth aspect, an embodiment of this application provides a data transmission apparatus. The apparatus includes: a determining unit, configured to determine a first performance parameter, where the first performance parameter indicates communication performance between the apparatus and a first station; and a providing unit, configured to provide a data transmission service for the first station when the first performance parameter satisfies a preset performance requirement. In a possible implementation, the apparatus further includes: a communication unit, configured to send network accessing information to a controller, where the network accessing information is information obtained by the apparatus when the first station accesses a network through the apparatus. The controller may send the network accessing information to a second access point controlled by the controller, so as to share the network accessing information among the access points controlled by the controller. In a possible implementation, the first station accesses a network through a second access point; and the apparatus further includes: the communication unit, configured to receive network accessing information of the first station from the controller, where the network accessing information is received by the controller from the second access point. In a possible implementation, the network accessing information includes association request information and a key. It may be understood that, the data transmission apparatus provided in the fourth aspect is configured to perform the corresponding method provided in the second aspect. Therefore, for beneficial effects that can be achieved by the data transmission apparatus, refer to the beneficial effects of the corresponding method provided in the second aspect. Details are not described herein again. According to a fifth aspect, an embodiment of this application provides a controller, including a processor, a memory, and a transceiver. The memory is configured to store computer instructions. When the controller runs, the processor executes the computer instructions, so that the controller performs the method provided in the first aspect. According to a sixth aspect, an embodiment of this application provides an access point, including a processor, a memory, and a transceiver. The memory is configured to store computer instructions. When the access point runs, the processor executes the computer instructions, so that the access point performs the method provided in the second aspect. According to a seventh aspect, an embodiment of this application provides a computer storage medium. The computer storage medium includes computer instructions. When the computer instructions are run on an electronic device, the electronic device performs the method provided in the first aspect. According to an eighth aspect, an embodiment of this application provides a computer storage medium. The computer storage medium includes computer instructions. When the computer instructions are run on an electronic device, the electronic device performs the method provided in the second aspect. According to a ninth aspect, an embodiment of this application provides a computer program product. When program code included in the computer program product is executed by a processor in an electronic device, the method provided in the first aspect is implemented. According to a tenth aspect, an embodiment of this application provides a computer program product. When program code included in the computer program product is executed by a processor in an electronic device, the method provided in the second aspect is implemented. According to an eleventh aspect, an embodiment of this application provides a chip system. The chip system includes a processor. The processor is configured to execute instructions, for a controller on which the chip system is installed to perform the method provided in the first aspect. According to a twelfth aspect, an embodiment of this application provides a chip system. The chip system includes a processor. The processor is configured to execute instructions, for an access point on which the chip system is installed to perform the method provided in the second aspect. According to a thirteenth aspect, an embodiment of this application provides an integrated circuit, including: a memory, configured to store instructions; and a processor coupled to the memory, configured to execute the instructions, to implement the method provided in the first aspect. According to a fourteenth aspect, an embodiment of this application provides an integrated circuit, including: a memory, configured to store instructions; and a processor coupled to the memory, configured to execute the instructions, to implement the method provided in the second aspect. According to the data transmission method and apparatus provided in embodiments of this application, based on a channel environment in which a station is located, one or more service access points may be selected for the station, and a data transmission mode between a plurality of service access points and the station may be selected, so that an optimal or optimal network access mode and an optimal or optimal data transmission mode are ensured for the station, thereby improving communication experience of users.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram of a fiber to the home network architecture; FIG. 2 is a schematic diagram of a fiber to the room network architecture; FIG. 3 is a schematic diagram of a Wi-Fi network architecture; FIG. 4 is a network logical architecture according to an embodiment of this application; FIG. 5 is a schematic diagram of a virtual cell according to an embodiment of this application; FIG. 6 is a flowchart of a data transmission method according to an embodiment of this application; FIG. 7 A and FIG. 7 B are a flowchart of a data transmission method according to an embodiment of this application; FIG. 8 A and FIG. 8 B are a flowchart of a data transmission method according to an embodiment of this application; FIG. 9 A and FIG. 9 B are a flowchart of a data transmission method according to an embodiment of this application; FIG. 10 is a flowchart of a data transmission method according to an embodiment of this application; FIG. 11 is a flowchart of a data transmission method according to an embodiment of this application; FIG. 12 is a schematic diagram of a structure of a data transmission apparatus according to an embodiment of this application; FIG. 13 is a schematic diagram of a structure of a data transmission apparatus according to an embodiment of this application; FIG. 14 is a schematic block diagram of a controller according to an embodiment of this application; FIG. 15 is a schematic block diagram of an access point according to an embodiment of this application; and FIG. 16 is a schematic block diagram of a chip system according to an embodiment of this application.

DESCRIPTION OF EMBODIMENTS

The following describes technical solutions in embodiments of the present invention with reference to accompanying drawings. It is clearly that the described embodiments are merely some rather than all of embodiments of this specification. In the descriptions of this specification, “an embodiment”, “some embodiments”, or the like indicates that one or more embodiments of this specification include specific features, structures, or characteristics described with reference to the embodiments. Therefore, statements such as “in an embodiment”, “in some embodiments”, “in some other embodiments”, and “in other embodiments” that appear at different places in this specification do not necessarily refer to a same embodiment. Instead, the statements mean “one or more but not all of embodiments”, unless otherwise specifically emphasized in another manner. In the descriptions of this specification, “/” means “or” unless otherwise specified. For example, A/B may represent A or B. In this specification, “and/or” describes only an association relationship between associated objects and represents that three relationships may exist. For example, A and/or B may represent the following three cases: Only A exists, both A and B exist, and only B exists. In addition, in the descriptions in embodiments of this specification, “a plurality of” means two or more than two. In the descriptions of this specification, the terms “first” and “second” are merely intended for description, and shall not be understood as an indication or implication of relative importance or implicit indication of a quantity of indicated technical features. Therefore, a feature limited by “first” or “second” may explicitly or implicitly include one or more features. The terms “comprise”, “include”, “have”, and their variants all mean “include but are not limited to”, unless otherwise specifically emphasized in another manner. A passive optical network (passive optical network, PON) is a technology that can provide fiber-optic communication services for home users. Generally, a PON includes an optical line terminal (optical line terminal, OLT) that serves as a network service provider endpoint and a plurality of optical network terminals (optical network terminals, ONTs) or optical network units (optical network units, ONUs) located on a user side. The OLT may be connected to a front-end (aggregation layer) switch by a network cable, and the OLT may be connected to an ONT (or an ONU) by an optical fiber. The OLT may be configured to perform conversion between an electrical signal and an optical signal, control and manage the ONT and ONU, and the like. The ONT or ONU may provide Wi-Fi network coverage. FIG. 1 shows a fiber to the home (fiber to the home, FTTH) network architecture, which is a conventional application architecture of the PON. As shown in FIG. 1 , in the FTTH network architecture, an OLT may be connected to a passive splitter (passive splitter) in an optical distribution network (optical distribution network, ODN) on a user side by an optical fiber. The OLT is connected to different ONTs or ONUs by different optical fibers through the passive splitter. In the FTTH architecture, different ONTs or ONUs may provide Wi-Fi coverage for different homes. Based on the FTTH architecture, a fiber to the room (fiber to the room, FTTR) architecture is provided. In the FTTR architecture, one or more ONTs may be configured in a single room in a home, so that the one or more ONTs may provide a network service for the single room, so as to improve bandwidth, latency, and coverage of a Wi-Fi network. The ONT in the FTTR architecture may also be referred to as an edge ONT (edge ONT). FIG. 2 shows an FTTR network architecture. An OLT may be connected to a plurality of ONTs in a same home by an optical fiber through a splitter. As shown in FIG. 2 , the plurality of ONTs may be deployed in different rooms in the home. For example, an ONT 1 is deployed in a room 1 , an ONT 2 is deployed in a room 2 , an ONT 3 is deployed in a room 3 , and the like. A controller configured to control the plurality of ONTs may be provided. The controller may also be referred to as a mini OLT (mini OLT). For example, the controller may be independent of the plurality of ONTs. Specifically, the controller may be independently provided, or may be integrated into a device other than the plurality of ONTs. For example, as shown in FIG. 2 , the controller may be integrated into a PON gateway. In this example, the controller may be connected to each of the plurality of ONTs by an optical fiber. For example, the controller may be integrated into one of the plurality of ONTs, for example, may be integrated into the ONT 1 . In this example, the ONT in which the controller is located may be connected to another ONT by an optical fiber. The ONT, the ONU, and the edge ONT may be devices carrying Wi-Fi chips, and may provide Wi-Fi network coverage for a station (station, STA). That is, the ONT, the ONU, and the edge ONT may serve as access points (access point, AP) for a terminal device to access a network. Therefore, in this embodiment of this application, the ONT, the ONU, and the edge ONT may be collectively referred to as access points. FIG. 3 shows a Wi-Fi network architecture. The network architecture may include a controller and a plurality of access points controlled by the controller. The plurality of access points may include an access point 1 , an access point 2 , an access point 3 , and the like. Each access point may provide Wi-Fi network coverage. For example, the controller may be integrated into one of the plurality of access points, for example, integrated into the access point 1 . In this example, the access point in which the controller is located may be connected to another access point by a Wi-Fi channel. For example, the controller may be independent of the plurality of access points, and may be connected to each of the plurality of access points by a Wi-Fi channel. In a solution, different access points have different basic service set identifiers (basic service set identifiers, BSSIDs), and one station can be connected to only one access point at one moment. Therefore, if the solution is used in the network architecture shown in FIG. 2 or FIG. 3 , each time a station needs to access an access point, the station and the access point need to undergo a complete station access process (including association, key agreement, and the like). In this case, when the station roams between different access points, a roaming switching time is long, causing service flow interruption, resulting in poor user experience. In addition, different terminal devices differ greatly. Some terminal devices may not support a Wi-Fi roaming protocol, and therefore, there is also a problem of non-roaming. In another solution, a same basic service set identifier may be configured for all access points in networking. Each access point may broadcast a beacon (beacon) frame carrying a basic service set identifier. After receiving the beacon frame, the station may perceive that the basic service set identifier of the access points in the networking is unique. When the station needs to access a new access point, the access point originally accessed by the station sends information required for connection, such as a key of the station, to the new access point in advance, so that the station can seamlessly roam to the new access point (where a roaming switching time is at a millimeter level, and basically no packet loss is caused). Although this solution can achieve seamless roaming, data transmission efficiency is low. As the basic service set identifiers of all the access points in the networking are the same, uplink data sent by the station may be received by a plurality of access points in the networking, and when receiving the uplink data, the plurality of access points reply with an acknowledge character (acknowledge character, ACK) or a block ACK (block ack, BA), consequently causing an ACK or BA conflict on a station side. In addition, in this solution, wireless bandwidth is low, which is difficult to satisfy the requirement of high bandwidth of a home network. In still another solution, a plurality of virtual access points (virtual access point, VAP) may be configured in an access point, and different access points have different basic service set identifiers. In other words, an access point may have a plurality of basic service set identifiers, and allocate one of the basic service set identifiers to a station. When a station moves to a coverage area of a new access point, the new access point may allocate a same basic service set identifier to the station, so that the station perceives that the basic service set identifier is unique, thereby achieving seamless roaming. In this solution, the access point needs to allocate different basic service set identifiers to different stations, which easily causes a conflict between the basic service set identifier and a basic service set identifier mask. In addition, the access point needs to broadcast beacon frames that carry different basic service set identifiers, resulting in high overheads of the beacon frames. Moreover, for an access point, a quantity of virtual access points that can be configured is limited, so that a quantity of stations connected to the access point is also limited. An embodiment of this application provides a data transmission method, which may be applied to the network architecture shown in FIG. 2 or FIG. 3 . A controller may select, based on communication performance between an access point and a station, one or more access points to cooperatively provide a data transmission service for the station; and when the one or more access points cooperatively provide the data transmission service for the station, the controller may select a data transmission mode between the one or more access points and the station. In this way, based on a channel environment between the access point and the station, an access point accessed by the station may be flexibly selected, and a data transmission mode between the access point and the station may be selected, so that an optimal wireless network access mode and an optimal data transmission mode are ensured for the station, thereby improving communication experience of users. The access point may be a communication device that supports one or more standards of 802.11ax, 802.11ac, 802.11n, 802.11g, 802.11b, 802.11a, and the like. For example, the access point may be the ONT or the ONU shown in FIG. 1 or FIG. 2 , or may be the access point shown in FIG. 3 . The station may be a terminal device such as a mobile phone, a notebook computer, a tablet computer, a wearable intelligent device, or an intelligent household appliance. The following describes a data transmission method provided in embodiments of this application by using examples in different embodiments. FIG. 4 shows a network logical architecture according to an embodiment of this application. The logical architecture may be provided in the network architecture shown in FIG. 2 or FIG. 3 . In the logical architecture, a controller A 1 may control a plurality of access points including an access point B 1 , an access point B 2 , and an access point B 3 , and the like. The controller A 1 may be integrated into the access point B 1 . The controller A 1 may be separately connected to access points other than the access point B 1 , such as the access point B 2 and the access point B 3 , by an optical fiber. A plurality of access points such as the access point B 1 , the access point B 2 , and the access point B 3 may have a same basic service set identifier C 1 . The same basic service set identifier may be manually configured, or may be automatically configured by the controller A 1 . The controller A 1 may control the access point B 1 , the access point B 2 , and the access point B 3 to select a same Wi-Fi channel (for example, a channel 36 ) as a fronthaul (fronthaul) channel, so as to subsequently provide a data transmission service for a same station in a cooperative manner. A station in coverage of an access point may access a network through the access point. For example, a station D 1 may access a network through the access point B 1 . That a station accesses a network means that a Wi-Fi link is established between the station and an access point, and data is exchanged through the Wi-Fi link, so that the station can access a network such as the Internet through the access point. Generally, for a Wi-Fi network, a process of network accessing of a station includes the following steps. S1. A station sends probe request (probe request) information to an access point. S2. The access point returns probe response (probe response) information to the station. S3. The station sends authentication request (authentication request) information to the access point. S4. The access point returns authentication response (authentication response) information to the station. S5. The station sends association request (association request) information to the access point. The association request information may also be referred to as an association request frame, and is necessary information for the access point to establish a connection to the station. The association request information includes capability information of the station (for example, a communication protocol supported by the station), so that the access point communicates with the station in a communication manner that satisfies a capability of the station. S6. The access point returns association response (association response) information to the station. Then, key agreement may be performed between the access point and the station, to generate a key for communication between the access point and the station. For a specific process of network accessing of the station, refer to descriptions of existing Wi-Fi related protocols. Details are not described herein again. As described above, the plurality of access points such as the access point B 1 , the access point B 2 , and the access point B 3 have the same basic service set identifier, and the association request information sent by the station when accessing a network may be received by the plurality of access points. Therefore, the plurality of access points may send the association response information to the station, causing a conflict and affecting the station to access the network. In some embodiments, to avoid the foregoing problem, each access point that receives the association request information sends, to the controller A 1 , the association request information received by each access point and a performance parameter that indicates communication performance between each access point and the station D 1 . The controller A 1 may determine, based on the performance parameter sent by each access point, an access point configured to respond to the association request information. Details are as follows. In an illustrative example, the performance parameter sent by an access point to the controller A 1 may include load information of the access point. It may be understood that the load information may indicate a busy degree of the Wi-Fi channel of the access point B 1 . A higher load indicates that the Wi-Fi channel is busier and the communication performance is lower. A lower load indicates that the Wi-Fi channel is idler and the communication performance is higher. For example, the load information may be a quantity of stations connected to the access point. For example, the load information may include a quantity and types of stations connected to the access point. Different station types correspond to different load weights. A correspondence between a station type and a load weight may be preset. For example, a load weight corresponding to a station type of a mobile phone is 1, a load weight corresponding to a station type of a VR device is 2, and a load weight corresponding to a station type of a smart refrigerator is 0.2. Therefore, the controller A 1 may determine a load of the access point based on the load information of the access point. For example, when the load information is a quantity of stations, a larger quantity of stations indicates a larger load of the access point. For example, when the load information includes a quantity and types of stations, a quantity of stations of a same type may be multiplied by a load weight corresponding to the type, to obtain a weighted load. Then, weighted loads of all station types are added to obtain a sum for indicating the load of the access point. In this illustrative example, the controller A 1 may select, based on the load of each access point, an access point configured to respond to the association request information. For example, the controller A 1 may receive association request information sent by the access point B 1 and load information of the access point B 1 , and may receive association request information sent by the access point B 2 and load information of the access point B 2 . Then, the controller A 1 determines whether the association request information sent by the access point B 1 and the association request information sent by the access point B 2 are from a same station; determines a load of the access point B 1 based on the load information sent by the access point B 1 ; and determines a load of the access point B 2 based on the load information sent by the access point B 2 . If the association request information sent by the access point B 1 and the association request information sent by the access point B 2 are from the same station (for example, the association request information sent by the access point B 1 and the association request information sent by the access point B 2 to the controller A 1 are both association request information sent by the station D 1 and received by the access point B 1 and the access point B 2 respectively), and the load of the access point B 1 is lower than the load of the access point B 2 , the controller A 1 may determine that the access point B 1 is an access point configured to respond to the association request information. In an illustrative example, the performance parameter sent by an access point to the controller A 1 may include a received signal strength indication (received signal strength indication, RSSI) of a Wi-Fi signal sent by the station D 1 and received by the access point. Specifically, the access point may measure the Wi-Fi signal sent by the station D 1 and received by the access point, to obtain the RSSI. It may be understood that the RSSI may reflect communication performance of a channel or a link. A higher RSSI indicates higher communication performance. In this illustrative example, the controller A 1 may select, based on the RSSI of the Wi-Fi signal sent by the station D 1 and received by the access point, an access point configured to respond to the association request information. For example, the controller A 1 may receive association request information sent by the access point B 1 and an RSSI of a Wi-Fi signal sent by the station D 1 and received by the access point B 1 , and may receive association request information sent by the access point B 2 and an RSSI of a Wi-Fi signal sent by the station D 1 and received by the access point B 2 . Then, the controller A 1 determines whether the association request information sent by the access point B 1 and the association request information sent by the access point B 2 are from a same station; and determines whether the RSSI of the Wi-Fi signal sent by the station D 1 and received by the access point B 1 is greater than the RSSI of the Wi-Fi signal sent by the station D 1 and received by the access point B 2 . If the association request information sent by the access point B 1 and the association request information sent by the access point B 2 are from the same station, and the RSSI of the Wi-Fi signal sent by the station D 1 and received by the access point B 1 is greater than the RSSI of the Wi-Fi signal sent by the station D 1 and received by the access point B 2 , the controller A 1 may determine that the access point B 1 is an access point configured to respond to the association request information. In an illustrative example, the performance parameter sent by an access point to the controller A 1 may include load information of the access point and an RSSI of a Wi-Fi signal sent by the station D 1 and received by the access point. The controller A 1 may determine, by comprehensively considering the load information of the access point and the RSSI of the Wi-Fi signal sent by the station D 1 and received by the access point, the access point configured to respond to the association request information. In an example, at least one access point that receives a Wi-Fi signal, sent by the station D 1 , whose RSSI is greater than a preset strength threshold may be determined, and then an access point with a minimum load in the at least one access point is determined as the access point configured to respond to the association request information. In an example, one or more access points whose loads are lower than a preset load threshold may be determined, and then an access point that is in the one or more access points and that receives a Wi-Fi signal, sent by the station D 1 , with a maximum RSSI is determined as the access point configured to respond to the association request information. It may be set that, through the foregoing solution, the controller A 1 may determine that the access point B 1 is the access point configured to respond to the association request information. In this way, through the foregoing solution, an access point (the access point B 1 ) configured to respond to the association request information can be determined. The access point (the access point B 1 ) configured to respond to the association request information sends association response information to the station D 1 , and another access point does not send association response information to the station D 1 , so that the station D 1 can access a network through a single point, thereby avoiding an access conflict caused by a same BSSID of a plurality of access points. After the station D 1 accesses a network through the access point B 1 , the access point B 1 may send network accessing information of the station D 1 to the controller A 1 . The controller A 1 may send the network accessing information to each access point controlled by the controller A 1 , so that the access points share the network accessing information. The network accessing information refers to information required for establishing a Wi-Fi link, and is cooperatively generated by the station and the access point when the station accesses a network. When the station accesses a network, the access point may obtain the network accessing information. For example, the network accessing information includes association request information and a key. The association request information is specifically association request information sent by the station to the access point in a network accessing process, and the key is a key on which the station and the access point agree in the network accessing process. In this way, a plurality of access points controlled by the controller A 1 may obtain the network accessing information of the station D 1 , so that a Wi-Fi link connected to the station D 1 can be established when a specific condition is satisfied. For example, each access point may obtain a performance parameter that indicates communication performance between the access point and the station D 1 , and determine whether the performance parameter satisfies a preset performance requirement E 1 . When the performance parameter satisfies the preset performance requirement E 1 , the access point may establish a Wi-Fi link connected to the station D 1 , so as to provide a data transmission service for the station D 1 . Each access point may send, to the controller A 1 , the performance parameter that indicates communication performance between the access point and the station D 1 . When the controller A 1 determines that the performance parameter satisfies the preset performance requirement E 1 , the controller A 1 may determine the access point that sends the performance parameter to provide a data transmission service for the station D 1 . In this way, the controller A 1 may determine, from a plurality of access points controlled by the controller A 1 , one or more access points configured to provide a data transmission service for the station D 1 . The one or more access points may form an access point set, to cooperatively provide a data transmission service for the station D 1 under control of the controller A 1 . The access points in the access point set jointly provide Wi-Fi network coverage for the station D 1 . For ease of description, the Wi-Fi network coverage that is provided by the access points in the access point set jointly for the station D 1 may be referred to as a virtual cell. For example, as shown in FIG. 5 , virtual cells of different stations may be determined in the foregoing manner. An access point B 1 and an access point B 2 may jointly provide a virtual cell F 1 for a station D 1 . The access point B 1 may provide a virtual cell F 2 for a station D 2 . The access point B 2 and an access point B 3 may jointly provide a virtual cell F 3 for a station D 3 . The following describes a performance parameter in embodiments of this application by using the access point B 1 and the station D 1 as an example. As described above, the performance parameter sent by the access point B 1 to the controller A 1 may indicate the communication performance between the access point B 1 and the station D 1 . That is, the performance parameter may include an indicator that indicates communication performance of a Wi-Fi link. In some embodiments, the performance parameter may include an RSSI of a Wi-Fi signal sent by the station D 1 and received by the access point B 1 . Correspondingly, the performance requirement E 1 includes a preset strength threshold G 1 . That the performance parameter satisfies the performance requirement E 1 includes that the RSSI is greater than the strength threshold G 1 . In some embodiments, the performance parameter sent by the access point B 1 to the controller may include load information of the access point B 1 . As described above, the load information may be a quantity of stations connected to the access point B 1 , or may be a quantity and types of stations connected to the access point B 1 . For details, refer to the foregoing descriptions. Details are not described herein again. Correspondingly, the performance requirement E 1 includes a preset load threshold H 1 . That the performance parameter satisfies the performance requirement E 1 includes that the load information (or a load determined based on the load information) is less than the load threshold H 1 . In some embodiments, the performance parameter may include both the RSSI and the load information. The performance requirement E 1 includes both the strength threshold G 1 and the load threshold H 1 . That the performance parameter satisfies the performance requirement E 1 includes both that the RSSI is greater than the strength threshold G 1 and that the load information (or a load determined based on the load information) is less than the load threshold H 1 . In some embodiments, the performance parameter sent by the access point B 1 to the controller may include a service type of a service executed by the station D 1 . It may be understood that different service types have different requirements on communication performance of a channel. It may be understood that, a high-demand service that requires low latency and high bandwidth, such as a VR service or a voice service, has a high requirement on communication performance of a channel. When a service type, included in the performance parameter, of a service that is executed by the station D 1 is a high-demand service, the controller A 1 may continue to perform the data transmission method provided in embodiments of this application, which is determining an access point set configured to jointly provide a data transmission service for the station D 1 . It may be understood that, a low-demand service such as a background (background, BK) service or a best effort (best effort, BE) service has a low requirement on communication. When a service type, included in the performance parameter, of a service that is executed by the station D 1 is a low-demand service, the controller A 1 may stop performing the data transmission method provided in embodiments of this application, and directly indicate an access point (for example, the access point B 1 ) to provide a data transmission service for the station D 1 . In some embodiments, each access point may periodically (for example, at one-second intervals or at other preset intervals) send a recently obtained performance parameter to the controller A 1 , or each access point may send a currently obtained performance parameter to the controller A 1 in real time. The controller A 1 may update, based on a performance parameter that is recently received by the controller A 1 and that is sent by each access point, the access point set configured to provide a data transmission service for the station, for the station to access a network in an optimal or optimal manner at different moments. In the foregoing manner, the controller A 1 may determine the access point set configured to provide a data transmission service for the station D 1 . The controller A 1 may further determine a data transmission mode between each access point and the station D 1 based on a performance parameter sent by each access point in the access point set. The following description is made by using an example. Refer to FIG. 6 . The controller A 1 may perform step 601 to determine an access point set P 1 configured to provide a data transmission service for the station D 1 . For details, refer to the foregoing descriptions. Details are not described herein again. When or after the access point set P 1 is determined, the controller A 1 may perform step 602 to determine whether a quantity of access points in the access point set P 1 is greater than 1. If the quantity of access points in the access point set P 1 is not greater than 1, the controller A 1 may perform step 603 to indicate an access point in the access point set P 1 to perform single-access-point transmission. For single-access-point transmission, refer to descriptions in a conventional technology. Details are not described herein again. In some embodiments, if the quantity of access points in the access point set P 1 is greater than 1, the controller A 1 may perform step 604 to determine whether all performance parameters sent by the access points in the access point set P 1 fail to satisfy a preset performance requirement E 2 . In other words, it is determined that no performance parameter sent by each access point satisfies the performance requirement E 2 . The performance requirement E 2 is higher than the performance requirement E 1 . In other words, the performance requirement E 2 is stricter than the performance requirement E 1 . For example, as described above, the performance parameter sent by each access point may include an RSSI. Correspondingly, the performance requirement E 2 may include a preset strength threshold G 2 , and the strength threshold G 2 is higher than the strength threshold G 1 . That no performance parameter sent by each access point in the access point set P 1 satisfies the preset performance requirement E 2 may specifically mean that an RSSI of each access point is less than the strength threshold G 2 . For example, as described above, the performance parameter sent by each access point may include load information. Correspondingly, the performance requirement E 2 may include a preset load threshold H 2 , and the load threshold H 2 is less than the load threshold H 1 . That no performance parameter sent by each access point in the access point set P 1 satisfies the preset performance requirement E 2 may specifically mean that load information (or a load determined based on the load information) of each access point is greater than the load threshold H 2 . For example, as described above, the performance parameter sent by each access point may include an RSSI and load information. Correspondingly, the performance requirement E 2 may include a preset strength threshold G 2 and a preset load threshold H 2 , the strength threshold G 2 is greater than the strength threshold G 1 , and the load threshold H 2 is less than the load threshold H 1 . That no performance parameter sent by each access point in the access point set P 1 satisfies the preset performance requirement E 2 may specifically mean that an RSSI of each access point is less than the strength threshold G 2 , and/or load information (or a load determined based on the load information) of each access point is greater than the load threshold H 2 . In a case that all performance parameters sent by the access points in the access point set P 1 fail to satisfy the performance requirement E 2 , in other words, when no performance parameter of each access point in the access point set P 1 satisfies the performance requirement E 2 , the controller A 1 may perform step 605 to determine that different access points in the access point set P 1 separately send same data to the station D 1 at different moments. For example, the controller A 1 or another network-side device (for example, a gateway) may send downlink data Q 1 whose destination is the station D 1 to each access point in the access point set P 1 . The controller A 1 configures a sending moment at which each access point sends the downlink data Q 1 to the station D 1 . Different access points have different sending moments. For example, the controller A 1 may send the downlink data Q 1 whose destination is the station D 1 to different access points in the access point set P 1 at different moments. When receiving the downlink data Q 1 , each access point may send the downlink data Q 1 to the station D 1 . In this way, different access points send the same data to the station D 1 at different moments, so that when a network environment of the station D 1 is poor, accuracy of receiving downlink data by the station D 1 can be ensured. In some embodiments, when the quantity of access points in the access point set P 1 is greater than 1, the controller A 1 may perform step 606 to determine whether all performance parameters sent by the access points in the access point set P 1 satisfy the performance requirement E 2 . For example, as shown in FIG. 6 , step 606 may be performed after step 604 . Specifically, when not all performance parameters sent by the access points in the access point set P 1 fail to satisfy the performance requirement E 2 , the controller A 1 may perform step 606 . For example, as described above, the performance parameter sent by each access point may include an RSSI. Correspondingly, the performance requirement E 2 may include a preset strength threshold G 2 , and the strength threshold G 2 is higher than the strength threshold G 1 . That all performance parameters sent by the access points in the access point set P 1 satisfy the preset performance requirement E 2 may specifically mean that an RSSI of each access point is not less than the strength threshold G 2 . For example, as described above, the performance parameter sent by each access point may include load information. Correspondingly, the performance requirement E 2 may include a preset load threshold H 2 , and the load threshold H 2 is less than the load threshold H 1 . That all performance parameters sent by the access points in the access point set P 1 satisfy the preset performance requirement E 2 may specifically mean that load information (or a load determined based on the load information) of each access point is not greater than the load threshold H 2 . For example, as described above, the performance parameter sent by each access point may include an RSSI and load information. Correspondingly, the performance requirement E 2 may include a preset strength threshold G 2 and a preset load threshold H 2 , the strength threshold G 2 is greater than the strength threshold G 1 , and the load threshold H 2 is less than the load threshold H 1 . That all performance parameters sent by the access points in the access point set P 1 satisfy the preset performance requirement E 2 may specifically mean that an RSSI of each access point is not less than the strength threshold G 2 , and load information (or a load determined based on the load information) of each access point is not greater than the load threshold H 2 . When all performance parameters sent by the access points in the access point set P 1 satisfy the performance requirement E 2 , the controller A 1 may perform step 607 to determine that different access points in the access point set P 1 separately send different data to the station D 1 at a same moment. For example, an access point in the access point set P 1 may send downlink data to the station D 1 in a distributed multiple-input multiple-output (multiple-input multiple-output, MIMO) manner. Specifically, the controller A 1 may notify each access point in the access point set P 1 to perform slot synchronization. Slot synchronization may be understood as clock synchronization. After slot synchronization, the access points in the access point set P 1 may use a same clock. The controller A 1 may further notify each access point in the access point P 1 to perform channel sounding. The access point B 1 is used as an example. The access point B 1 may send a channel sounding signal (for example, a null data packet (null data packet, NDP)) to the station D 1 . The station D 1 may send a channel sounding result (for example, a feedback null data packet (feedback NDP)) to the access point B 1 in response to the channel sounding signal. The access point B 1 may report the channel sounding result to the controller A 1 . Each access point in the access point set P 1 may report a channel sounding result to the controller A 1 . The controller A 1 may determine, based on the channel sounding result reported by each access point, a precoding matrix for performing distributed MIMO. The precoding matrix may include a precoding vector (vector) corresponding to each access point. The controller A 1 may separately deliver the precoding vector to the corresponding access point. Then, the access points may send different downlink data to the station by using the precoding vectors of the access points, so as to implement multi-channel concurrency. The foregoing merely describes the solution of distributed MIMO as an example. For a detailed solution, refer to the 802.11 be protocol. Details are not described herein again. In some embodiments, when determining results of both step 604 and step 606 are no, that is, when performance parameters sent by some access points in the access point set P 1 satisfy the performance requirement E 2 , and performance parameters sent by the other access points do not satisfy the performance requirement E 2 , the controller A 1 may perform step 608 to determine a primary access point from the access point set P 1 , where the primary access point is configured to independently provide a data transmission service for the station D 1 . Specifically, the controller A 1 may use an access point whose sent performance parameter satisfies the performance requirement E 2 as a primary access point, and control the primary access point to provide a data transmission service for the station D 1 , and the other access points no longer provide a data transmission service for the station D 1 . For example, when there are a plurality of access points whose sent performance parameters satisfy the performance requirement E 2 , one of the access points may be determined as a primary access point. For example, an access point with a minimum load or a maximum RSSI may be determined as the primary access point. In an illustrative example of these embodiments, the data transmission service in step 608 may specifically refer to a downlink data transmission service. That is, the controller A 1 controls the primary access point to send downlink data received from a network side to the station D 1 , and the other access points no longer send downlink data to the station D 1 . In another illustrative example of these embodiments, the data transmission service in step 608 may include an uplink data transmission service and a downlink data transmission service. That is, the controller A 1 indicates the primary access point to provide an uplink data transmission service and a downlink data transmission service for the station D 1 . The other access points no longer receive or process uplink data sent by the station D 1 , and no longer send downlink data to the station D 1 . According to the foregoing solution, when the network environment of the station D 1 is poor (all performance parameters sent by the access points in the access point set P 1 fail to satisfy the performance requirement E 2 ), different access points may separately send same data to the station D 1 , so that a probability that the station D 1 receives downlink data can be increased. Alternatively, when the network environment of the station D 1 is good (all performance parameters sent by the access points in the access point set P 1 satisfy the performance requirement E 2 ), different access points may simultaneously send different data to the station D 1 , so that a data throughput is increased. Alternatively, when the network environment of the station D 1 is average (performance parameters sent by some access points in the access point set P 1 satisfy the performance requirement E 2 , and performance parameters sent by the other access points do not satisfy the performance requirement E 2 ), an access point with good communication performance with the station D 1 may be indicated to provide a data transmission service for the station. Therefore, an optimal network access mode and an optimal data transmission mode can be provided for the station D 1 , thereby improving communication experience of users. The following describes, in a specific example, the data transmission method provided in embodiments of this application. FIG. 7 A and FIG. 7 B show a data transmission method according to an embodiment of this application. The method may be applied to a scenario in which a channel environment of a station is poor. As shown in FIG. 7 A and FIG. 7 B , a station D 1 and an access point B 1 may perform a network accessing process or procedure of the station D 1 , so that the station D 1 can access a network through the access point B 1 . For a specific network accessing process, refer to the foregoing description of steps S1 to S6. Details are not described herein again. After the station D 1 accesses a network through the access point B 1 , the access point B 1 may perform step 702 to send, to a controller A 1 , network accessing information obtained by the access point B 1 when the station D 1 accesses the network. For details about the network accessing information, refer to the foregoing descriptions. Details are not described herein again. The controller A 1 may send the introduced network accessing information to an access point B 2 through step 703 a , and send the network accessing information to an access point B 3 through step 703 b. In some embodiments, the access point B 1 may obtain a performance parameter R 1 that indicates communication performance between the access point B 1 and the station D 1 , and perform step 704 a to determine that the performance parameter R 1 satisfies a performance requirement E 1 and then add the station D 1 to an associated list of the access point B 1 . For details about the performance parameter and the performance requirement E 1 , refer to the foregoing description. A station in the associated list is a station connected to the access point B 1 . That is, a Wi-Fi link is established between a station in the associated list and the access point B 1 . In some embodiments, the access point B 2 may obtain a performance parameter R 2 that indicates communication performance between the access point B 2 and the station D 1 , and perform step 704 b to determine that the performance parameter R 2 satisfies a performance requirement E 1 and then add the station D 1 to an associated list of the access point B 2 . In step 704 b , when or after determining that the performance parameter R 2 satisfies the performance requirement E 1 , the access point B 2 may establish a Wi-Fi link between the access point B 2 and the station D 1 based on the network accessing information received from the controller A 1 . In some embodiments, the access point B 3 may obtain a performance parameter R 3 that indicates communication performance between the access point B 3 and the station D 1 , and perform step 704 c to determine that the performance parameter R 3 does not satisfy a performance requirement E 1 and then add the station D 1 to an unassociated list of the access point B 3 . A station in the unassociated list is a station that is not connected to the access point B 3 . The access point B 1 may perform step 705 a to send the performance parameter R 1 to the controller A 1 . The access point B 2 may perform step 705 b to send the performance parameter R 2 to the controller A 1 . The access point B 3 may perform step 705 c to send the performance parameter R 3 to the controller A 1 . Then, the controller A 1 may determine, based on the performance parameter R 1 , the performance parameter R 2 , and the performance parameter R 3 , an access point set P 1 configured to provide a data transmission service for the station D 1 . Specifically, the controller A 1 may perform step 706 to determine that the performance parameter R 1 and the performance parameter R 2 satisfy the performance requirement E 1 , and to determine that the performance parameter R 3 does not satisfy the performance requirement E 1 , and further determine that the access point B 1 and the access point B 2 cooperatively provide a data transmission service for the station D 1 . That is, when the performance parameter R 1 and the performance parameter R 2 satisfy the performance requirement E 1 , but the performance parameter R 3 does not satisfy the performance requirement E 1 , the access point B 1 and the access point B 2 form an access point set P 1 configured to provide a data transmission service for the station D 1 , and the access point B 3 is not included in the access point set P 1 . Still refer to FIG. 7 B . The controller A 1 may perform step 707 to determine that the performance parameter R 1 and the performance parameter R 2 do not satisfy a performance requirement E 2 , and further determine that the access point B 1 and the access point B 2 send same data to the station D 1 at different moments. The data transmission mode in which different access points separately send same data to the station at different moments may be referred to as a data backup transmission mode. The performance parameter R 1 and the performance parameter R 2 do not satisfy the performance requirement E 2 , indicating that a channel environment in which the station D 1 is located is poor. To avoid loss or retransmission of a large amount of data packets, the controller A 1 selects the data backup transmission mode. In some embodiments, when or after determining that the access point B 1 and the access point B 2 send the same data to the station D 1 at different moments, the controller A 1 may perform step 708 a and step 708 b . Specifically, in step 708 a , configuration information Y 1 is sent to the access point B 1 . The configuration information Y 1 may include a sending moment T 1 of downlink data. The configuration information Y 1 may indicate the access point B 1 to send downlink data Q 1 to the station D 1 at the sending moment T 1 . The access point B 1 may perform step 709 at the moment T 1 in response to the configuration information Y 1 , to send the downlink data Q 1 to the station D 1 . The downlink data Q 1 is received by the access point B 1 from a network-side device (for example, a gateway or the controller A 1 ). In step 708 b , configuration information Y 2 is sent to the access point B 2 . The configuration information Y 2 includes a sending moment T 2 of downlink data. The configuration information Y 2 may indicate the access point B 2 to send downlink data Q 1 to the station D 1 at the sending moment T 2 . The downlink data Q 1 is received by the access point B 2 from a network-side device (for example, a gateway or the controller A 1 ). Therefore, when the downlink data Q 1 is successfully transmitted on at least one channel, the station D 1 can successfully receive the downlink data Q 1 . Steps 707 to 710 describe a solution of downlink data transmission. The data transmission method provided in this embodiment of this application may further include a solution of uplink data transmission. Details are as follows. In some embodiments, still refer to FIG. 7 B . After step 706 , the controller A 1 may perform step 711 a to send configuration information Y 3 to the access point B 1 , where the configuration information Y 3 includes a sending moment T 3 of uplink resource configuration information. The controller A 1 may further perform step 711 b to send configuration information Y 4 to the access point B 1 , where the configuration information Y 4 includes a sending moment T 4 of uplink resource configuration information. The moment T 4 is later than the moment T 3 . The configuration information Y 3 may indicate the access point B 1 to send uplink resource configuration information Z 1 to the station D 1 at the sending moment T 3 . The access point B 1 may perform step 712 in response to the configuration information Y 3 , to send the uplink resource configuration information Z 1 to the station D 1 . It may be understood that the uplink resource configuration information indicates a frequency domain resource and a time domain resource that are used by the station to send uplink data. For example, the configuration information Y 3 may further indicate that a delay resource for uplink transmission allocated by the access point B 1 to the station D 1 is the moment T 4 . In other words, the uplink resource configuration information Z 1 may indicate the station D 1 to send an uplink transmission resource at the moment T 4 . If successfully receiving the uplink resource configuration information Z 1 , the station D 1 may perform step 713 to send uplink data to the access point B 1 at the moment T 4 . The configuration information Y 4 may indicate the access point B 2 to send uplink resource configuration information to the station D 1 at the sending moment T 4 . The configuration information Y 4 may indicate that the access point B 2 no longer sends the uplink resource configuration information to the station D 1 when the station sends the uplink data at the sending moment T 4 . Back to FIG. 4 , the access point B 2 and the access point B 1 communicate with the station D 1 on a same channel (for example, a channel 36 ). When the access point B 2 sends the uplink resource configuration information to the station D 1 at the moment T 4 , it is detected that an air interface or a Wi-Fi channel of the station D 1 is occupied, indicating that the station D 1 is sending uplink data. In this case, the access point B 2 no longer sends the uplink resource configuration information to the station D 1 . For example, that the access point B 2 no longer sends the uplink resource configuration information to the station D 1 specifically means that the access point B 2 no longer sends the uplink resource configuration information to the station D 1 until receiving configuration information that is delivered by the controller A 1 next time and that indicates sending of an uplink resource. In addition, it may be understood that the uplink data sent in step 713 is transmitted by using an uplink transmission resource configured by the access point B 1 . The access point B 1 receives and processes the uplink data, and replies with an acknowledge character (ACK or BA) for the uplink data. However, the access point B 2 no longer processes the uplink data, and does not reply with an acknowledge character (ACK or BA) for the uplink data. Therefore, a conflict caused when a plurality of access points send acknowledge characters is avoided. In some embodiments, the uplink resource configuration information described above may be specifically a trigger (trigger) frame in the 802.11ax protocol. The uplink data sent in step 713 may be specifically carried in a trigger-based physical-layer protocol data unit (trigger-based physical-layer protocol data unit, TB PPDU). It is to be noted that although step 701 to step 713 are shown in a sequence in FIG. 7 A and FIG. 7 B , an execution sequence of these steps is not limited. In some embodiments, step 701 to step 713 may be performed according to the sequence shown in FIG. 7 A and FIG. 7 B . In some embodiments, step 701 to step 713 may be performed in another sequence. For example, steps 708 a , 708 b , 711 a , and 711 b may be performed in parallel. In another example, step 712 may be performed before step 709 , and the like, this is not listed herein one by one. In the data transmission method provided in this embodiment of this application, when a channel environment in which the station is located is poor, the plurality of access points may send the same data to the station, thereby increasing a probability that the station successfully receives the data. FIG. 8 A and FIG. 8 B show a data transmission method according to an embodiment of this application. The method may be applied to a scenario in which a channel environment of a station is good. For step 801 to step 806 shown in FIG. 8 A , refer to the foregoing descriptions of step 701 to step 706 in FIG. 7 A . Details are not described herein again. Refer to FIG. 8 B . After step 806 , the controller A 1 may perform step 807 to determine that both the performance parameter R 1 and the performance parameter R 2 satisfy the performance requirement E 2 , and further determine that the access point B 1 and the access point B 2 may send different data to the station D 1 at a same moment. For example, the data transmission mode in which different access points may separately send different data to the station at a same moment may be referred to as a distributed MIMO mode. Both the performance parameter R 1 and the performance parameter R 2 satisfy the performance requirement E 2 , indicating that a channel environment in which the station D 1 is located is good, and the distributed MIMO transmission mode may be used, so as to implement multi-channel concurrency and increase a data throughput of a network. In some embodiments, when or after determining that the access point B 1 and the access point B 2 may send different data to the station D 1 at the same moment, the controller A 1 may perform step 808 a to send a slot synchronization message and a channel sounding notification to the access point B 1 , and may perform step 808 b to send a slot synchronization message and a channel sounding notification to the access point B 2 . The slot synchronization message indicates an access point to perform slot synchronization or clock synchronization. For example, the slot synchronization message sent in step 808 a and the slot synchronization message sent in step 808 b include a same calibration clock, so that the access point B 1 and the access point B 2 can perform slot synchronization or clock synchronization according to the calibration clock. In this way, slot synchronization between the access point B 1 and the access point B 2 is implemented. The channel sounding notification indicates an access point to send a channel sounding signal to a station. For example, the channel sounding signal may be an NDP. Therefore, the access point B 1 may perform step 809 a in response to the channel sounding notification, to send a channel sounding signal U 1 to the station D 1 . When or after receiving the channel sounding signal U 1 , the station D 1 may detect a related indicator (for example, a level or signal strength) of the channel sounding signal U 1 , and may determine a channel sounding result W 1 based on a detection result. The channel sounding result W 1 may be a feedback NDP. The station D 1 may perform step 810 a to send the channel sounding result W 1 to the access point B 1 . Then, the access point B 1 may send the channel sounding result W 1 to the controller A 1 through step 811 a . Similarly, the access point B 2 may perform step 809 b in response to the channel sounding notification, to send a channel sounding signal U 2 to the station D 1 . The station D 1 may perform step 810 b according to the channel sounding signal U 2 , to send a channel sounding result W 2 to the access point B 2 . The access point B 2 may report the channel sounding result W 2 to the controller A 1 through step 811 b. When or after obtaining the channel sounding result W 1 and the channel sounding result W 2 , the controller A 1 may determine a precoding matrix based on the channel sounding result W 1 and the channel sounding result W 2 . For details, refer to the description of the 802.11be protocol, and details are not described herein again. The determined precoding matrix may include a precoding vector V 1 corresponding to the access point B 1 and a precoding vector V 2 corresponding to the access point B 2 . Then, the controller A 1 may perform step 812 a to send the precoding vector V 1 to the access point B 1 , and may perform step 812 b to send the precoding vector V 2 to the access point B 2 . The access point B 1 may perform step 813 a according to the precoding vector V 1 , to send downlink data Q 2 to the station D 1 . The access point B 2 may perform step 813 b according to the precoding vector V 2 , to send downlink data Q 3 to the station D 1 . Step 813 a and step 813 b may be performed at the same time. In addition, the solution of sending downlink data when a channel environment in which a station is located is good is described above. Uplink data may be sent by using the solution described in the embodiment shown in FIG. 7 A and FIG. 7 B . For details, refer to the foregoing descriptions of step 711 a to step 713 in FIG. 7 B . Details are not described herein again. In this way, when a channel environment in which the station is located is good, the plurality of access points connected to the station may simultaneously send different data to the station, thereby increasing a data throughput of a network. FIG. 9 A and FIG. 9 B show a data transmission method according to an embodiment of this application. The method may be applied to a scenario in which a channel environment of a station is average. For step 901 to step 906 shown in FIG. 9 A , refer to the foregoing descriptions of step 701 to step 706 in FIG. 7 A . Details are not described herein again. Refer to FIG. 9 B . After step 906 , the controller A 1 may perform step 907 to determine that the performance parameter R 1 satisfies the performance requirement E 2 and that the performance parameter R 2 does not satisfy the performance requirement E 2 . Further, it is determined that the access point B 1 is a primary access point configured to independently provide a data transmission service for the station D 1 . For example, the data transmission mode in which one of a plurality of access points simultaneously connected to a station serves as a primary access point to independently provide a data transmission service for the station may be referred to as an access point primary/secondary switching mode. The performance parameter R 1 satisfies the performance requirement E 2 , but the performance parameter R 2 does not satisfy the performance requirement E 2 , indicating that a channel environment in which the station D 1 is located is average, and an access point having good communication performance with the station is used to independently provide a data transmission service for the station, so that both communication quality of service and overall network overheads can be ensured. In some embodiments, refer to FIG. 9 B . The controller A 1 may be used as a network-side device of an access point, and may perform step 908 a to send downlink data whose destination is the station D 1 to the primary access point, namely, the access point B 1 . Then, the access point B 1 may perform step 909 to send the downlink data to the station D 1 . However, the controller A 1 does not send the downlink data whose destination is the station D 1 to the access point B 2 . In some embodiments, the controller A 1 may be used as a management device of an access point, and may perform step 908 b to send configuration information Y 5 to the access point B 2 . The configuration information Y 5 is used to prohibit the access point B 2 from responding to data sent by the station D 1 . In other words, the access point B 2 no longer returns an acknowledge character (for example, ACK or BA) to the station D 1 according to the configuration information Y 5 when receiving uplink data sent by the station D 1 through step 910 . The access point B 1 returns an acknowledge character (for example, ACK or BA) to the station D 1 when receiving the uplink data sent by the station D 1 through step 910 . In this way, a conflict caused when a plurality of access points return acknowledge characters can be avoided. In some embodiments, the controller A 1 may not perform step 908 b , but the uplink transmission solution in the embodiment shown in FIG. 7 A and FIG. 7 B is adopted, to avoid a conflict caused when a plurality of access points return acknowledge characters. According to the data transmission method provided in this embodiment of this application, when a channel environment in which the station is located is average, an access point having good communication performance with the station may be selected to provide a data transmission service for the station, so that both communication quality of service of the station and overall network overheads can be ensured. In conclusion, embodiments of this application provide a data transmission method. The method may be performed by a controller configured to control a plurality of access points, for example, the controller A 1 described above. Refer to FIG. 10 . The method may include the following steps. Step 1001 : The controller receives a performance parameter sent by each of the access points, where the performance parameter indicates communication performance between the access point that sends the performance parameter and a first station. In an example, for implementation of step 1001 , refer to the foregoing descriptions of step 705 a to step 705 c in FIG. 7 A . Details are not described herein again. Step 1003 : The controller determines, based on each received performance parameter, an access point set configured to provide a data transmission service for the first station, where the access point set includes at least one of the plurality of access points. In an example, for implementation of step 1003 , refer to the foregoing description of step 706 in FIG. 7 A . Step 1005 : When the access point set includes at least two access points, the controller determines a data transmission mode between each of the access points in the access point set and the first station based on the performance parameter sent by each of the access points in the access point set. In an example, for implementation of step 1005 , refer to the foregoing description of step 707 in FIG. 7 B , step 807 in FIG. 8 B , or step 907 in FIG. 9 B . In some embodiments, the performance parameter includes at least one of a received signal strength indication RSSI of a signal sent by the first station and received by the access point, and load information of the access point. For example, the performance parameter sent by any access point in the determined access point set satisfies that the RSSI is greater than a preset strength threshold, and the load information is less than a preset load threshold. In some embodiments, the controller is independent of each of the plurality of access points, or the controller is integrated into one of the plurality of access points. In some embodiments, when the controller is independent of each of the plurality of access points, the controller receives, over an optical link or a Wi-Fi channel, the performance parameter sent by each of the access points; or when the controller is integrated into one of the plurality of access points, the controller receives, over an optical link or a Wi-Fi channel, the performance parameter sent by each of the access points except the access point in which the controller is located. In some embodiments, the plurality of access points include a first access point and a second access point, and the first station accesses a network through the first access point; and the method further includes: receiving, by the controller, network accessing information of the first station from the first access point; and sending, by the controller, the network accessing information to the second access point. For details, refer to the foregoing descriptions of step 701 to step 703 b in FIG. 7 A . For example, the network accessing information includes association request information and a key. For example, the plurality of access points include a same basic service set identifier BSSID. In some embodiments, the determining, by the controller, a data transmission mode between each of the access points in the access point set and the first station based on the performance parameter sent by each of the access points in the access point set includes: when the performance parameter corresponding to each of the access points in the access point set does not satisfy a preset performance requirement, determining that different access points in the access point set separately send same data to the first station at different moments. For details, refer to the foregoing descriptions of steps 707 to 710 in FIG. 7 B . In some embodiments, the determining, by the controller, a data transmission mode between each of the access points in the access point set and the first station based on the performance parameter sent by each of the access points in the access point set includes: when the performance parameter corresponding to each of the access points in the access point set satisfies a preset performance requirement, determining that different access points in the access point set separately send different data to the first station at a same moment. For details, refer to the foregoing descriptions of steps 807 to 813 b in FIG. 8 B . In some embodiments, the determining, by the controller, a data transmission mode between each of the access points in the access point set and the first station based on the performance parameter sent by each of the access points in the access point set includes: when a performance parameter of a third access point in the access point set satisfies a preset performance requirement, and access points in the access point set except the third access point do not satisfy the performance requirement, configuring the third access point as a primary access point in the access point set, where the primary access point is configured to independently send data to the first station. For details, refer to the foregoing descriptions of steps 907 to 909 in FIG. 9 B . For example, when receiving first data sent by the first station, the primary access point is further configured to send an acknowledge character corresponding to the first data to the first station. For details, refer to the foregoing descriptions of steps 908 b to 911 in FIG. 9 B . In some embodiments, the access point set includes a fourth access point and a fifth access point; and the determining, by the controller, a data transmission mode between each of the access points in the access point set and the first station based on the performance parameter sent by each of the access points in the access point set includes: configuring a sending moment at which the fourth access point sends uplink resource configuration information to the first station as a first moment; and configuring a sending moment at which the fifth access point sends the uplink resource configuration information to the first station as a second moment, where the second moment is later than the first moment; and when the first station sends uplink data at the second moment in response to the uplink resource configuration information sent by the fourth access point, the fifth access point no longer sends the uplink resource configuration information to the first station. For details, refer to the foregoing descriptions of steps 711 a to 713 in FIG. 7 B . According to the data transmission method provided in this embodiment of this application, based on a channel environment in which a station is located, one or more service access points may be selected for the station, and a data transmission mode between a plurality of service access points and the station may be selected, so that an optimal network access mode and an optimal data transmission mode are ensured for the station, thereby improving communication experience of users. An embodiment of this application provides a data transmission method, which may be applied to a first access point in a plurality of access points controlled by a controller, for example, the access point B 1 described above. Refer to FIG. 11 . The method includes the following steps. Step 1101 : The first access point determines a first performance parameter, where the first performance parameter indicates communication performance between the first access point and a first station. In an example, for implementation of step 1101 , refer to the foregoing descriptions of steps 704 a to 704 c in FIG. 7 A . Step 1103 : Provide a data transmission service for the first station when the first performance parameter satisfies a preset performance requirement. In an example, for implementation of step 1103 , refer to the foregoing descriptions of steps 704 a to 706 in FIG. 7 A . In some embodiments, the method further includes: sending, by the first access point, network accessing information to the controller, where the network accessing information is information obtained by the first access point when the first station accesses a network through the first access point. For details, refer to the foregoing descriptions of steps 702 to 703 b in FIG. 7 A . Details are not described herein again. In some embodiments, the plurality of access points further include a second access point; the first station accesses a network through the second access point; and the method further includes: receiving, by the first access point, network accessing information of the first station from the controller, where the network accessing information is received by the controller from the second access point. For details, refer to the foregoing description of step 703 a in FIG. 7 A . In some embodiments, the network accessing information includes association request information and a key. According to the data transmission method provided in this embodiment of this application, an access point can determine, based on a channel environment between the access point and a station, whether to provide a network service for the station, thereby ensuring both network quality of service of the station and overall network overheads. Refer to FIG. 12 . An embodiment of this application provides a data transmission apparatus 1200 , including: a communication unit 1210 , a first determining unit 1220 , and a second determining unit 1230 . The communication unit 1210 is configured to receive a performance parameter sent by each of the access points, where the performance parameter indicates communication performance between the access point that sends the performance parameter and a first station. The first determining unit 1220 is configured to determine, based on each received performance parameter, an access point set configured to provide a data transmission service for the first station, where the access point set includes at least one of the plurality of access points. The second determining unit 1230 is configured to determine, when the access point set includes at least two access points, a data transmission mode between each of the access points in the access point set and the first station based on the performance parameter sent by each of the access points in the access point set. For functions of functional units of the apparatus 1200 , refer to the foregoing description of the method embodiment shown in FIG. 10 . Details are not described herein again. According to the data transmission apparatus provided in this embodiment of this application, based on a channel environment in which a station is located, one or more service access points may be selected for the station, and a data transmission mode between a plurality of service access points and the station may be selected, so that an optimal network access mode and an optimal data transmission mode are ensured for the station, thereby improving communication experience of users. Refer to FIG. 13 . An embodiment of this application provides a data transmission apparatus 1300 , including: a determining unit 1310 and a providing unit 1320 . The determining unit 1310 is configured to determine a first performance parameter, where the first performance parameter indicates communication performance between the apparatus and a first station. The providing unit 1320 is configured to provide a data transmission service for the first station when the first performance parameter satisfies a preset performance requirement. For functions of functional units of the apparatus 1300 , refer to the foregoing description of the method embodiment shown in FIG. 11 . Details are not described herein again. The data transmission apparatus provided in this embodiment of this application can determine, based on a channel environment between the data transmission apparatus and a station, whether to provide a network service for the station, thereby ensuring both network quality of service of the station and overall network overheads. The apparatus provided in embodiments of this application is mainly described above from a perspective of a method process. It may be understood that, to implement the foregoing functions, each electronic device includes a corresponding hardware structure and/or software module for implementing each function. A person skilled in the art should easily be aware that, in combination with units and algorithm steps of the examples described in the embodiments disclosed in this specification, this application can be implemented by hardware or a combination of hardware and computer software. Whether a function is performed by hardware or hardware driven by computer software depends on particular applications and design constraints of the technical solutions. A person skilled in the art may use different methods to implement the described functions for each particular application, but it should not be considered that the implementation goes beyond the scope of this application. Refer to FIG. 14 . An embodiment of this application provides a controller 1400 . The controller 1400 may perform the operations performed by the controller A 1 in the method embodiments shown in FIG. 4 , FIG. 6 , FIG. 7 A and FIG. 7 B , FIG. 8 A and FIG. 8 B , FIG. 9 A and FIG. 9 B , or FIG. 10 . The controller 1400 may include a processor 1410 , a memory 1420 , and a transceiver 1430 . The memory 1420 stores instructions, and the instructions may be executed by the processor 1410 . When the instructions are executed by the processor 1410 , the controller 1400 may perform the operations performed by the controller A 1 in the method embodiments shown in FIG. 4 , FIG. 6 , FIG. 7 A and FIG. 7 B , FIG. 8 A and FIG. 8 B , FIG. 9 A and FIG. 9 B , or FIG. 10 . Specifically, the processor 1410 may perform a data processing operation, and the transceiver 1430 may perform a data sending and/or receiving operation. Refer to FIG. 15 . An embodiment of this application provides an access point 1500 . The access point 1500 may perform the operations performed by the access point in the method embodiments shown in FIG. 4 , FIG. 6 , FIG. 7 A and FIG. 7 B , FIG. 8 A and FIG. 8 B , FIG. 9 A and FIG. 9 B , or FIG. 11 , for example, the operations performed by the access point B 1 . The access point 1500 may include a processor 1510 , a memory 1520 , and a transceiver 1530 . The memory 1520 stores instructions, and the instructions may be executed by the processor 1510 . When the instructions are executed by the processor 1510 , the access point 1500 may perform the operations performed by the access point in the method embodiments shown in FIG. 4 , FIG. 6 , FIG. 7 A and FIG. 7 B , FIG. 8 A and FIG. 8 B , FIG. 9 A and FIG. 9 B , or FIG. 11 , for example, the operations performed by the access point B 1 . Specifically, the processor 1510 may perform a data processing operation, and the transceiver 1530 may perform a data sending and/or receiving operation. Refer to FIG. 16 . An embodiment of this application provides a chip system, which may be configured in the foregoing controller A 1 . As shown in FIG. 16 , the chip system includes a processor 1610 and an interface circuit 1620 . The processor 1610 is connected to the interface circuit 1620 , and is configured to perform the operations performed by the controller A 1 in the method embodiments shown in FIG. 4 , FIG. 6 , FIG. 7 A and FIG. 7 B , FIG. 8 A and FIG. 8 B , FIG. 9 A and FIG. 9 B , or FIG. 10 . In some embodiments, the chip system further includes a memory 1630 . The memory stores instructions, and the instructions may be executed by the processor 1610 . When the instructions are executed by the processor 1610 , the chip system may perform the operations performed by the controller A 1 in the method embodiments shown in FIG. 4 , FIG. 6 , FIG. 7 A and FIG. 7 B , FIG. 8 A and FIG. 8 B , FIG. 9 A and FIG. 9 B , or FIG. 10 . Still refer to FIG. 16 . An embodiment of this application provides a chip system, which may be configured in the access point described above, for example, the access point B 1 or the access point B 2 . As shown in FIG. 16 , the chip system includes a processor 1610 and an interface circuit 1620 . The processor 1610 is connected to the interface circuit 1620 , and is configured to perform the operations performed by the access point in the method embodiments shown in FIG. 4 , FIG. 6 , FIG. 7 A and FIG. 7 B , FIG. 8 A and FIG. 8 B , FIG. 9 A and FIG. 9 B , or FIG. 11 . In some embodiments, the chip system further includes a memory 1630 . The memory stores instructions, and the instructions may be executed by the processor 1610 . When the instructions are executed by the processor 1610 , the chip system may perform the operations performed by the access point in the method embodiments shown in FIG. 4 , FIG. 6 , FIG. 7 A and FIG. 7 B , FIG. 8 A and FIG. 8 B , FIG. 9 A and FIG. 9 B , or FIG. 11 . It may be understood that the processor in embodiments of this application may be a central processing unit (central processing unit, CPU), or may be another general-purpose processor, a digital signal processor (digital signal processor, DSP), an application-specific integrated circuit (application-specific integrated circuit, ASIC), a field-programmable gate array (field-programmable gate array, FPGA) or another programmable logic device, a transistor logic device, a hardware component, or any combination thereof. The general-purpose processor may be a microprocessor or any regular processor. The method steps in embodiments of this application may be implemented by hardware, or may be implemented by a processor executing software instructions. The software instructions may include corresponding software modules. The software modules may be stored in a random access memory (random access memory, RAM), a flash memory, a read-only memory (read-only memory, ROM), a programmable read-only memory (programmable ROM, PROM), an erasable programmable read-only memory (erasable PROM, EPROM), an electrically erasable programmable read-only memory (electrically EPROM, EEPROM), a register, a hard disk, a removable hard disk, a CD-ROM, or any other form of storage medium well-known in the art. For example, a storage medium is coupled to a processor, so that the processor can read information from the storage medium and write information into the storage medium. Certainly, the storage medium may be a component of the processor. The processor and the storage medium may be disposed in an ASIC. All or some of the foregoing embodiments may be implemented by using software, hardware, firmware, or any combination thereof. When software is used to implement the embodiments, all or some of the embodiments may be implemented in a form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all of some of the procedures or functions according to embodiments of this application are generated. The computer may be a general-purpose computer, a dedicated computer, a computer network, or another programmable apparatus. The computer instructions may be stored in a computer-readable storage medium, or may be transmitted by using the computer-readable storage medium. The computer instructions may be transmitted from a website, computer, server, or data center to another website, computer, server, or data center in a wired (for example, a coaxial cable, an optical fiber, or a digital subscriber line (DSL)) or wireless (for example, infrared, radio, or microwave) manner. The computer-readable storage medium may be any usable medium accessible by the computer, or a data storage device, for example, a server or a data center, integrating one or more usable media. The usable medium may be a magnetic medium (for example, a floppy disk, a hard disk, or a magnetic tape), an optical medium (for example, a DVD), a semiconductor medium (for example, a solid-state drive (solid-state drive, SSD)), or the like. It may be understood that various numbers in embodiments of this application are merely used for differentiation for ease of description, and are not used to limit the scope of embodiments of this application.